OLYMPIA -- This spring's recreational razor clam season on Washington's Pacific Ocean beaches is being postponed and may not open at all due to elevated levels of domoic acid, the departments of Fish and Wildlife and Health announced today.

Domoic acid can cause amnesic shellfish poisoning in humans.

Bimonthly tests conducted by the state Department of Health during the fall and winter have shown domoic acid levels in razor clams remain above 15 parts per million. Domoic acid concentrations above that level can induce amnesic shellfish poisoning. Tests will continue to determine when the razor clams are safe to eat.

Symptoms, which can occur within 24 hours of consuming clams with high levels of domoic acid include nausea, vomiting, diarrhea or abdominal cramps. In severe cases, headaches, dizziness, disorientation, seizures, breathing difficulties, memory loss and even death may occur within 48 hours of consuming the clams.

Only razor clams are affected by the domoic acid. Other recreational and commercial shellfish are safe to eat.